Many ports depend on other ports. There are seven variables that you can use to ensure
that all the required bits will be on the user's machine. There are also some
pre-supported dependency variables for common cases, plus a few more to control the
behavior of dependencies.

This variable specifies the shared libraries this port depends on. It is a list of
lib:dir[:target] tuples where lib is the name of the shared library, dir is the directory in which to find it in case it is not
available, and target is the target to call in that
directory. For example,

LIB_DEPENDS=
jpeg.9:${PORTSDIR}/graphics/jpeg:install

will check for a shared jpeg library with major version 9, and descend into the graphics/jpeg subdirectory of your ports tree to build and install
it if it is not found. The target part can be omitted if
it is equal to DEPENDS_TARGET (which defaults to install).

Note: The lib part is an argument given to ldconfig -r | grep -wF. There shall be no regular expressions in
this variable.

The dependency is checked twice, once from within the extract target and then from within the install target. Also, the name of the dependency is put into the
package so that pkg_add(1) will
automatically install it if it is not on the user's system.

This variable specifies executables or files this port depends on during run-time. It
is a list of path:dir[:target] tuples where path is the name of the executable or file, dir is the directory in which to find it in case it is not
available, and target is the target to call in that
directory. If path starts with a slash (/), it is treated as a file and its existence is tested with test -e; otherwise, it is assumed to be an executable, and which -s is used to determine if the program exists in the search
path.

will check if the file or directory /usr/local/etc/innd
exists, and build and install it from the news/inn subdirectory
of the ports tree if it is not found. It will also see if an executable called wish8.0 is in the search path, and descend into the x11-toolkits/tk80 subdirectory of your ports tree to build and
install it if it is not found.

Note: In this case, innd is actually an executable; if
an executable is in a place that is not expected to be in the search path, you should use
the full pathname.

The dependency is checked from within the install target.
Also, the name of the dependency is put into the package so that pkg_add(1) will
automatically install it if it is not on the user's system. The target part can be omitted if it is the same as DEPENDS_TARGET.

If there is a dependency that does not fall into either of the above categories, or
your port requires having the source of the other port extracted in addition to having it
installed, then use this variable. This is a list of dir[:target], as there is nothing to check, unlike the
previous four. The target part can be omitted if it is the
same as DEPENDS_TARGET.

A number of variables exist in order to encapsulate common dependencies that many
ports have. Although their use is optional, they can help to reduce the verbosity of the
port Makefiles. Each of them is styled as USE_*. The usage of these variables
is restricted to the port Makefiles and ports/Mk/bsd.*.mk and is not designed to encapsulate user-settable
options -- use WITH_* and WITHOUT_* for that purpose.

Note: It is always
incorrect to set any USE_* in /etc/make.conf. For instance, setting

USE_GCC=3.2

would adds a dependency on gcc32 for every port, including gcc32 itself!

Table 5-1. The USE_*
variables

Variable

Means

USE_BZIP2

The port's tarballs are compressed with bzip2.

USE_ZIP

The port's tarballs are compressed with zip.

USE_GMAKE

The port requires gmake to build.

USE_PERL5

The port requires perl 5 to build and install. See Section 6.3 for additional variables that can be set relating
to perl.

USE_X_PREFIX

The port installs in to X11BASE rather than PREFIX. See Section 6.4 for additional
variables that can be set relating to X11.

USE_AUTOMAKE_VER

The port uses GNU automake as part of its build process. See
Section 6.5 for additional variables that can be set
relating to automake.

USE_AUTOCONF_VER

The port uses GNU autoconf as part of its build process. See
Section 6.5 for additional variables that can be set
relating to autoconf.

USE_LIBTOOL_VER

The port uses GNU libtool as part of its build process. See
Section 6.5 for additional variables that can be set
relating to libtool.

GMAKE

The full path for gmake if it is not in the PATH.

USE_BISON

The port uses bison for building.

USE_SDL

The port uses SDL for building and running. See Section 6.13 on how to use USE_SDL.

NO_INSTALL_MANPAGES

Do not use the install.man target.

Define USE_XLIB=yes if your port requires the X Window
System to be installed (it is implied by USE_IMAKE). Define USE_GMAKE=yes if your port requires GNU make instead of BSD make. Define USE_AUTOCONF_VER=213 if your port requires GNU autoconf to be run.
Define USE_QT_VER=3 if your port uses the latest Qt toolkit.
Use USE_PERL5=yes if your port requires version 5 of the perl language. (The last is especially important since some
versions of FreeBSD have perl5 as part of the base system
while others do not.)

As mentioned above, the default target to call when a dependency is required is DEPENDS_TARGET. It defaults to install. This is a user variable; it is never defined in a port's
Makefile. If your port needs a special way to handle a
dependency, use the :target part of the *_DEPENDS variables instead of redefining DEPENDS_TARGET.

When you type make clean, its dependencies are automatically
cleaned too. If you do not wish this to happen, define the variable NOCLEANDEPENDS in your environment. This may be particularly
desirable if the port has something that takes a long time to rebuild in its dependency
list, such as KDE, GNOME or Mozilla.

To depend on another port unconditionally, use the variable ${NONEXISTENT} as the first field of BUILD_DEPENDS or RUN_DEPENDS. Use this only
when you need to get the source of the other port. You can often save compilation time by
specifying the target too. For instance

BUILD_DEPENDS= ${NONEXISTENT}:${PORTSDIR}/graphics/jpeg:extract

will always descend to the jpeg port and extract it.

Do not use DEPENDS unless there is no other way the behavior
you want can be accomplished. It will cause the other port to always be built (and
installed, by default), and the dependency will go into the packages as well. If this is
really what you need, you should probably write it as BUILD_DEPENDS and RUN_DEPENDS
instead--at least the intention will be clear.

Important: Do not introduce any circular dependencies into the ports tree!

The ports building technology does not tolerate circular dependencies. If you
introduce one, you will have someone, somewhere in the world, whose FreeBSD installation
will break almost immediately, with many others quickly to follow. These can really be
hard to detect; if in doubt, before you make that change, make sure you have done the
following: cd /usr/ports; make index. That process can be quite
slow on older machines, but you may be able to save a large number of people--including
yourself-- a lot of grief in the process.